Satellites around Edge-on Galaxies. I. Dynamical Masses

Abstract: We have undertaken a search for satellites around edge-on galaxies in the EGIPS catalog, which contains 16551 objects with declinations above -30 deg. We searched for systems with a central galaxy dominating in brightness by at least 1 mag compared to its companions. As a result, we discovered 1097 candidate satellites around 764 EGIPS galaxies with projected distances less than 500 kpc and a radial velocity difference less than 300 km/s. Of these, 757 satellites around 547 central galaxies have radial velocity accuracies higher than 20 km/s and satisfy the gravitationally bound condition. The ensemble of satellites is characterized by an average projected distance of 84 kpc and an average radial velocity dispersion of 103 km/s. Treating small satellites as test particles moving on isotropic orbits around central EGIPS galaxies, we determined the projected (orbital) masses of the edge-on galaxies. Within the luminosity range of 1.3*10^10 to 42*10^{10} Lsun, the total mass of the systems is well described by a linear dependence log(Mp)~0.88*log(<LK>g) with an average total mass-to-$K$-band luminosity equal to 17.5+-0.8 Msun/Lsun, which is typical for nearby spiral galaxies such as the Milky Way, M 31 and M 81.